Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

With a wav file for example you can easily distinguish between bit depths

24-bit

Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, 
                    s32, 2116 kb/s

16-bit

Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo,
                    s16, 1411 kb/s

However AAC seems inscrutable

Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo,
                         fltp, 151 kb/s
share|improve this question

1 Answer 1

up vote 4 down vote accepted

AAC is a lossy format (like MP3), and as Wikipedia (indeed, the same article you linked to) explains:

Technically speaking, bit depth is only meaningful when applied to pure PCM devices. Non-PCM formats, such as lossy compression systems like MP3, have bit depths that are not defined in the same sense as PCM. In lossy audio compression, where bits are allocated to other types of information, the bits actually allocated to individual samples are allowed to fluctuate within the constraints imposed by the allocation algorithm.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.